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Message-ID: <8d931037-500f-1dff-5fb6-fe60d2e8af7d@linux.intel.com>
Date: Thu, 28 Sep 2023 09:58:38 +0800
From: Baolu Lu <baolu.lu@...ux.intel.com>
To: Jingqi Liu <Jingqi.liu@...el.com>, iommu@...ts.linux.dev,
Tian Kevin <kevin.tian@...el.com>,
Joerg Roedel <joro@...tes.org>, Will Deacon <will@...nel.org>,
Robin Murphy <robin.murphy@....com>
Cc: baolu.lu@...ux.intel.com, linux-kernel@...r.kernel.org
Subject: Re: [PATH v3 2/3] iommu/vt-d: debugfs: Create/remove debugfs file per
{device, pasid}
On 9/27/23 11:15 PM, Jingqi Liu wrote:
> Add a debugfs directory per pair of {device, pasid} if the mappings of
> its page table are created and destroyed by the iommu_map/unmap()
> interfaces. i.e. /sys/kernel/debug/iommu/intel/<device source id>/<pasid>.
> Create a debugfs file in the directory for users to dump the page
> table corresponding to {device, pasid}. e.g.
> /sys/kernel/debug/iommu/intel/0000:00:02.0/0/domain_translation_struct.
>
> When attaching device without pasid, create a debugfs file with
> PASID#0, i.e. RID_PASID. When attaching a domain to a pasid of device,
> create a debugfs file with the specified pasid.
>
> When detaching without pasid, remove the directory and file for
> PASID#0. When detaching with pasid, remove the debugfs directory and
> file of the specified pasid. Remove the entire debugfs directory of
> the specified device for releasing device.
> e.g. /sys/kernel/debug/iommu/intel/0000:00:01.0
>
> Signed-off-by: Jingqi Liu <Jingqi.liu@...el.com>
> ---
> drivers/iommu/intel/debugfs.c | 133 ++++++++++++++++++++++++++++++++--
> drivers/iommu/intel/iommu.c | 29 ++++++++
> drivers/iommu/intel/iommu.h | 12 +++
> 3 files changed, 169 insertions(+), 5 deletions(-)
>
> diff --git a/drivers/iommu/intel/debugfs.c b/drivers/iommu/intel/debugfs.c
> index e2a3c37943a0..50dea53ba87c 100644
> --- a/drivers/iommu/intel/debugfs.c
> +++ b/drivers/iommu/intel/debugfs.c
> @@ -32,6 +32,11 @@ struct iommu_regset {
> const char *regs;
> };
>
> +struct show_domain_info {
> + struct device *dev;
> + ioasid_t pasid;
> +};
> +
> #define DEBUG_BUFFER_SIZE 1024
> static char debug_buf[DEBUG_BUFFER_SIZE];
>
> @@ -111,6 +116,8 @@ static const struct iommu_regset iommu_regs_64[] = {
> IOMMU_REGSET_ENTRY(VCRSP),
> };
>
> +static struct dentry *intel_iommu_debug;
> +
> static int iommu_regset_show(struct seq_file *m, void *unused)
> {
> struct dmar_drhd_unit *drhd;
> @@ -673,16 +680,12 @@ static const struct file_operations dmar_perf_latency_fops = {
>
> void __init intel_iommu_debugfs_init(void)
> {
> - struct dentry *intel_iommu_debug = debugfs_create_dir("intel",
> - iommu_debugfs_dir);
> + intel_iommu_debug = debugfs_create_dir("intel", iommu_debugfs_dir);
>
> debugfs_create_file("iommu_regset", 0444, intel_iommu_debug, NULL,
> &iommu_regset_fops);
> debugfs_create_file("dmar_translation_struct", 0444, intel_iommu_debug,
> NULL, &dmar_translation_struct_fops);
> - debugfs_create_file("domain_translation_struct", 0444,
> - intel_iommu_debug, NULL,
> - &domain_translation_struct_fops);
> debugfs_create_file("invalidation_queue", 0444, intel_iommu_debug,
> NULL, &invalidation_queue_fops);
> #ifdef CONFIG_IRQ_REMAP
> @@ -692,3 +695,123 @@ void __init intel_iommu_debugfs_init(void)
> debugfs_create_file("dmar_perf_latency", 0644, intel_iommu_debug,
> NULL, &dmar_perf_latency_fops);
> }
> +
> +/* Create a debugfs directory for each device. */
> +void intel_iommu_debugfs_create_dev(struct device *dev)
> +{
> + struct dentry *dev_dir;
> +
> + dev_dir = debugfs_lookup(dev_name(dev), intel_iommu_debug);
> + if (!dev_dir) {
> + dev_dir = debugfs_create_dir(dev_name(dev), intel_iommu_debug);
> + if (IS_ERR(dev_dir))
> + pr_info("%s: Failed to create debugfs directory.\n",
> + dev_name(dev));
> + } else
> + dput(dev_dir);
> +}
Above could simply be like this:
void intel_iommu_debugfs_create_dev(struct device *dev)
{
struct device_domain_info *info = dev_iommu_priv_get(dev);
info->debugfs_entry = debugfs_create_dir(dev_name(dev),
intel_iommu_debug);
}
Isn't it?
> +
> +void intel_iommu_debugfs_remove_dev(struct device *dev)
> +{
> + struct dentry *dev_dir, *sub_dir, *dentry;
> + struct list_head *plist;
> +
> + dev_dir = debugfs_lookup(dev_name(dev), intel_iommu_debug);
> + if (!dev_dir)
> + return;
> +
> + list_for_each(plist, &(dev_dir->d_subdirs)) {
> + sub_dir = list_entry(plist, struct dentry, d_child);
> + if(sub_dir) {
> + dentry = debugfs_lookup("domain_translation_struct",
> + sub_dir);
> + if (!dentry)
> + continue;
> +
> + if (dentry->d_inode->i_private)
> + kfree(dentry->d_inode->i_private);
> +
> + dput(dentry);
> + }
> + }
> +
> + debugfs_remove_recursive(dev_dir);
> + dput(dev_dir);
> +}
And this could simply be like this:
void intel_iommu_debugfs_remove_dev(struct device *dev)
{
struct device_domain_info *info = dev_iommu_priv_get(dev);
debugfs_remove(info->debugfs_entry);
}
> +
> +/*
> + * Create a debugfs directory per pair of {device, pasid},
> + * then create the corresponding debugfs file in this directory
> + * for user to dump its page table. e.g.
> + * /sys/kernel/debug/iommu/intel/0000:00:01.0/0/domain_translation_struct
> + */
> +void intel_iommu_debugfs_create_dev_pasid(struct iommu_domain *domain,
> + struct device *dev, u32 pasid)
> +{
> + struct dentry *dev_dir, *pasid_dir;
> + struct show_domain_info *sinfo;
> + char dir_name[10];
> +
> + /*
> + * The debugfs only dumps the page tables whose mappings are created
> + * and destroyed by the iommu_map/unmap() interfaces. Check the
> + * mapping type of the domain before creating debugfs directory.
> + */
> + if (!domain || !(domain->type & __IOMMU_DOMAIN_PAGING))
> + return;
> +
> + dev_dir = debugfs_lookup(dev_name(dev), intel_iommu_debug);
> + if (!dev_dir)
> + return;
> +
> + sprintf(dir_name, "%x", pasid);
> + pasid_dir = debugfs_create_dir(dir_name, dev_dir);
> + if (IS_ERR(pasid_dir))
> + goto dput_out;
> +
> + sinfo = kzalloc(sizeof(*sinfo), GFP_KERNEL);
> + if (!sinfo)
> + goto dput_out;
> +
> + sinfo->dev = dev;
> + sinfo->pasid = pasid;
> + debugfs_create_file("domain_translation_struct", 0444,
> + pasid_dir, sinfo,
> + &domain_translation_struct_fops);
> +dput_out:
> + dput(dev_dir);
> +}
And here,
void intel_iommu_debugfs_create_dev_pasid(struct iommu_domain *domain,
struct device *dev, u32 pasid)
{
sprintf(dir_name, "%x", pasid);
dev_pasid->debugfs_entry = debugfs_create_dir(dir_name,
info->debugfs_entry);
debugfs_create_file("domain_translation_struct", 0444,
dev_pasid->debugfs_entry, dev_pasid,
&domain_translation_struct_fops);
}
> +
> +/*
> + * Remove the debugfs directory and file corresponding to each pair of
> + * {device, pasid}.
> + */
> +void intel_iommu_debugfs_remove_dev_pasid(struct device *dev, u32 pasid)
> +{
> + struct dentry *dev_dir, *pasid_dir, *dentry;
> + char dir_name[10];
> +
> + dev_dir = debugfs_lookup(dev_name(dev), intel_iommu_debug);
> + if (!dev_dir)
> + return;
> +
> + sprintf(dir_name, "%x", pasid);
> + pasid_dir = debugfs_lookup(dir_name, dev_dir);
> + if (!pasid_dir)
> + goto dput_dev;
> +
> + dentry = debugfs_lookup("domain_translation_struct", pasid_dir);
> + if (!dentry)
> + goto dput_pasid;
> +
> + if (dentry->d_inode->i_private)
> + kfree(dentry->d_inode->i_private);
> +
> + debugfs_remove_recursive(pasid_dir);
> +
> + dput(dentry);
> +dput_pasid:
> + dput(pasid_dir);
> +dput_dev:
> + dput(dev_dir);
> +}
The same thing here:
debugfs_remove(dev_pasid->debugfs_entry);
> diff --git a/drivers/iommu/intel/iommu.c b/drivers/iommu/intel/iommu.c
> index dd8ff358867d..af9c989035a2 100644
> --- a/drivers/iommu/intel/iommu.c
> +++ b/drivers/iommu/intel/iommu.c
> @@ -2488,6 +2488,13 @@ static int dmar_domain_attach_device(struct dmar_domain *domain,
>
> iommu_enable_pci_caps(info);
>
> + /*
> + * Create a debugfs directory specified by RID_PASID
> + * in the debugfs device directory.
> + */
> + intel_iommu_debugfs_create_dev_pasid(&info->domain->domain,
> + dev, IOMMU_NO_PASID);
The function name is self-explained. So no need to add comments. Ditto
to all other places.
> +
> return 0;
> }
>
> @@ -3997,6 +4004,12 @@ static void device_block_translation(struct device *dev)
>
> domain_detach_iommu(info->domain, iommu);
> info->domain = NULL;
> +
> + /*
> + * Remove the debugfs directory specified by RID_PASID
> + * in the device debugfs directory.
> + */
> + intel_iommu_debugfs_remove_dev_pasid(dev, IOMMU_NO_PASID);
> }
>
> static int md_domain_init(struct dmar_domain *domain, int guest_width)
> @@ -4424,6 +4437,9 @@ static struct iommu_device *intel_iommu_probe_device(struct device *dev)
> }
> }
>
> + /* Create a debugfs directory per device. */
> + intel_iommu_debugfs_create_dev(dev);
> +
> return &iommu->iommu;
> }
>
> @@ -4436,6 +4452,7 @@ static void intel_iommu_release_device(struct device *dev)
> dev_iommu_priv_set(dev, NULL);
> kfree(info);
> set_dma_ops(dev, NULL);
> + intel_iommu_debugfs_remove_dev(dev);
> }
>
> static void intel_iommu_probe_finalize(struct device *dev)
> @@ -4729,6 +4746,12 @@ static void intel_iommu_remove_dev_pasid(struct device *dev, ioasid_t pasid)
> out_tear_down:
> intel_pasid_tear_down_entry(iommu, dev, pasid, false);
> intel_drain_pasid_prq(dev, pasid);
> +
> + /*
> + * Remove the debugfs directory of the specified pasid
> + * in the device debugfs directory.
> + */
> + intel_iommu_debugfs_remove_dev_pasid(dev, pasid);
> }
>
> static int intel_iommu_set_dev_pasid(struct iommu_domain *domain,
> @@ -4777,6 +4800,12 @@ static int intel_iommu_set_dev_pasid(struct iommu_domain *domain,
> list_add(&dev_pasid->link_domain, &dmar_domain->dev_pasids);
> spin_unlock_irqrestore(&dmar_domain->lock, flags);
>
> + /*
> + * Create a debugfs directory with specified pasid
> + * in the debugfs device directory.
> + */
> + intel_iommu_debugfs_create_dev_pasid(domain, dev, pasid);
> +
> return 0;
> out_detach_iommu:
> domain_detach_iommu(dmar_domain, iommu);
> diff --git a/drivers/iommu/intel/iommu.h b/drivers/iommu/intel/iommu.h
> index c18fb699c87a..f1c27e928886 100644
> --- a/drivers/iommu/intel/iommu.h
> +++ b/drivers/iommu/intel/iommu.h
> @@ -883,8 +883,20 @@ static inline void intel_svm_remove_dev_pasid(struct device *dev, ioasid_t pasid
>
> #ifdef CONFIG_INTEL_IOMMU_DEBUGFS
> void intel_iommu_debugfs_init(void);
> +void intel_iommu_debugfs_create_dev(struct device *dev);
> +void intel_iommu_debugfs_create_dev_pasid(struct iommu_domain *domain,
> + struct device *dev, u32 pasid);
> +void intel_iommu_debugfs_remove_dev(struct device *dev);
> +void intel_iommu_debugfs_remove_dev_pasid(struct device *dev, u32 pasid);
> #else
> static inline void intel_iommu_debugfs_init(void) {}
> +static inline void intel_iommu_debugfs_create_dev(struct device *dev) {}
> +static inline
> +void intel_iommu_debugfs_create_dev_pasid(struct iommu_domain *domain,
> + struct device *dev, u32 pasid) {}
> +static inline void intel_iommu_debugfs_remove_dev(struct device *dev) {}
> +static inline
> +void intel_iommu_debugfs_remove_dev_pasid(struct device *dev, u32 pasid) {}
> #endif /* CONFIG_INTEL_IOMMU_DEBUGFS */
>
> extern const struct attribute_group *intel_iommu_groups[];
Best regards,
baolu
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